Hormone

hormone

[hor´mōn]

a chemical transmitter substance produced by cells of the body and transported by the bloodstream to the cells and organs on which it has a specific regulatory effect. adj., adj hormo´nal. Hormones act as chemical messengers to body organs, stimulating certain life processes and retarding others. Growth, reproduction, control of metabolic processes, sexual attributes, and even mental conditions and personality traits are dependent on hormones.

Hormones are produced by various organs and body tissues, but mainly by the endocrine glands, such as the pituitary, thyroid, and gonads (testes and ovaries). Each gland apparently synthesizes several kinds of hormones; the adrenal glands alone produce more than 25 varieties. The total number of hormones is still unknown, but each has its unique function and its own chemical formula. After a hormone is discharged by its parent gland into the capillaries or the lymph, it may travel a circuitous path through the bloodstream to exert influence on cells, tissues, and organs (target organs) far removed from its site of origin.

One of the best-known endocrine hormones is insulin, a protein manufactured by the beta cells of the islands of Langerhans in the pancreas that is important in carbohydrate metabolism. Other important hormones are thyroxine, an iodine-carrying amino acid produced by the thyroid gland; cortisone, a member of the steroid family from the adrenal glands; and the sex hormones, estrogen from the ovaries and androgen from the testes. Certain hormone substances can be synthesized in the laboratory for treatment of human disease. Animal hormones can also be used, as endocrine hormones are to some extent interchangeable among species. Extracts from the pancreas of cattle, for example, enabled diabetes sufferers to live normal lives even before the chemistry of insulin was fully understood.

Endocrine hormone synthesis and secretion is controlled and regulated by a closed-loop system. Negative feedback loops maintain optimal levels of each hormone in the body. If there are abnormally high levels of a hormone in the blood, feedback to the gland responsible for its production inhibits secretion. If there are abnormally low levels, the gland is stimulated to step up production and secretion. In this way a homeostatic balance is maintained. (See also endocrine glands.)

adrenocortical hormone

1. any of the corticosteroids secreted by the adrenal cortex, the major ones being the glucocorticoids and mineralocorticoids, and including some androgens, progesterone, and estrogens.

corticotropin-releasing hormone (CRH) a neuropeptide secreted by the median eminence of the hypothalamus that binds to specific receptors on the corticotroph cells of the anterior pituitary and stimulates the secretion of corticotropin.

ectopic h's those secreted by tumors of nonendocrine tissues but having the same physiologic effects as their normally produced counterparts. It is not known exactly how the synthesis and secretion of endocrine hormones from nonendocrine tissues occurs. Most of these tumors are derived from tissues that have a common embryonic origin with endocrine tissues. When the cells undergo neoplastic transformation, they can revert to a more primitive stage of development and begin to synthesize hormones.

Ectopic hormones present serious problems for patients and add to the complexity of caring for those with certain kinds of neoplastic diseases. These hormones do not respond to the feedback mechanisms that regulate normal hormonal production; hence, surgery and destruction of the tumorous tissue by radiation and chemotherapy are the treatments of choice.

follicle-stimulating hormone (FSH) one of the gonadotropins of the anterior pituitary, which stimulates the growth and maturity of graafian follicles in the ovary, and stimulates spermatogenesis in the male.

growth hormone–releasing hormone (GH-RH) a neuropeptide elaborated by the median eminence of the hypothalamus that binds to specific receptors on the somatotroph cells of the anterior pituitary and stimulates the secretion of growth hormone.

local hormone a substance with hormone like properties that acts at an anatomically restricted site; most are rapidly degraded. Called also autacoid and autocoid.

luteinizing hormone (LH) a gonadotropin of the anterior pituitary gland, acting with follicle-stimulating hormone to cause ovulation of mature follicles and secretion of estrogen by thecal and granulosa cells of the ovary; it is also concerned with corpus luteum formation. In the male, it stimulates development of the interstitial cells of the testes and their secretion of testosterone. Called also interstitial cell–stimulating hormone.

melanocyte-stimulating hormone (MSH) a substance from the anterior pituitary gland of certain other animals but not humans; it influences the formation or deposition of melanin in the body and pigmentation of the skin.

thyrotropin-releasing hormone (TRH) a tripeptide hormone of the hypothalamus, which stimulates release of thyrotropin from the pituitary gland. In humans, it also acts as a prolactinreleasing factor. It is used in the diagnosis of mild hyperthyroidism and Graves disease, and in differentiating between primary, secondary, and tertiary hypothyroidism.

hor·mone

(hōr'mōn),

A chemical substance, formed in one organ or part of the body and carried in the blood to another organ or part where they exert functional effects; depending on the specificity of their effects, hormones can alter the functional activity, and sometimes the structure, of just one organ or tissue or various numbers of them. Various hormones are formed by ductless glands, but molecules such as secretin, cholecystokinin/somatostatin, formed in the gastrointestinal tract, by definition are also hormones. The definition of hormone has been recently extended to chemical substances formed by cells and acting on neighboring cells (that is, paracrine function) or the same cells that produce them (that is, autocrine function). For hormones not listed below, see specific names.

[G. hormōn, pres. part. of hormaō, to rouse or set in motion]

hormone

/hor·mone/ (hor´mōn) a chemical substance produced in the body which has a specific regulatory effect on the activity of certain cells or a certain organ or organs.hormo´nal

adrenocortical hormone

1. any of the corticosteroids elaborated by the adrenal cortex, the major ones being the glucocorticoids and mineralocorticoids, and including some androgens, progesterone, and perhaps estrogens.

growth hormone (GH) any of several related hormones secreted by the adenohypophysis that directly influence protein, carbohydrate, and lipid metabolism and control the rate of skeletal and visceral growth; used pharmaceutically as somatrem and somatropin.

inhibiting hormones hormones elaborated by one body structure that inhibit release of hormones from another structure; applied to substances of established clinical identity, while those whose chemical structure is still unknown are called inhibiting factors.

luteinizing hormone–releasing hormone (LH-RH) a glycoprotein gonadotropic hormone of the adenohypophysis that acts with follicle-stimulating hormone to promote ovulation and promotes secretion of androgen and progesterone. A preparation of the salts is used in the differential diagnosis of hypothalamic, pituitary, and gonadal dysfunction and in the treatment of some forms of infertility and hypogonadism.

melanocyte-stimulating hormone , melanophore-stimulating hormone (MSH) one of several peptides secreted by the anterior pituitary in humans and in the rhomboid fossa in lower vertebrates, influencing melanin formation and deposition in the body and causing color changes in the skin of amphibians, fishes, and reptiles.

releasing hormones hormones elaborated in one structure that cause the release of hormones from another structure; applied to substances of established chemical identity, while those whose chemical structure is unknown are called releasing factors.

hormone

a. A substance, usually a peptide or steroid, produced by one tissue and conveyed by the bloodstream to another to effect physiological activity, such as growth or metabolism.

b. A synthetic compound that acts like a hormone in the body.

2. Any of various similar substances found in plants and insects that regulate development.

hor·mon′al(-mō′nəl), hor·mon′ic(-mŏn′ĭk) adj.

hor·mon′al·ly adv.

hormone

[hôr′mōn]

Etymology: Gk, hormaein, to set in motion

a complex chemical substance produced in one part or organ of the body that initiates or regulates the activity of an organ or a group of cells in another part. Hormones secreted by the endocrine glands are carried through the bloodstream to the target organ. Secretion of these hormones is regulated by other hormones, by neurotransmitters, and by a negative feedback system in which an excess of target organ activity or hormone signals a decreased need for the stimulating hormone. Other hormones are released by organs for local effect, most commonly in the digestive tract.

hormone

A biomolecule released by a cell or gland that transfers information and instructions from one group of cells to another.

hor·mone

A chemical substance formed in a tissue or organ and carried in the blood; stimulates or inhibits the growth or function of one or more other tissues or organs.

[G. hormōn, pres. part. of hormaō, to rouse or set in motion]

hormone

a chemical that is produced in the body of a plant or animal, sometimes in very small quantities, and which, when transported (usually by the blood stream in animals) to the target site in another part of the organism, elicits a particular response. In animals the ductless glands that secrete hormones are called ENDOCRINE ORGANS. Animal hormones that influence other endocrine glands are called trophins (or tropins) - for example, GONADOTROPHINS. PLANT HORMONES are usually called growth substances.

Hormone

Hormones are chemicals that are produced in an organ or gland and then are carried by the blood to another part of the body where they produce a special effect for which they were designed.

hormone

a substance (peptide or steroid) released from secretory cells, mainly those that constitute the endocrine (ductless) glands, into the blood stream; taken up by specific cellular receptors elsewhere in the body and thereby activating some particular cellular process. For sources, chemical nature and actions, Table 1.

hormone (hōrˑ·mōn),

n a chemical transmitter produced by endocrine glands.

hor·mone

(hōr'mōn)

A chemical substance, formed in one organ or part of the body and carried in the blood to another organ or part where it produces functional effects; depending on the specificity of their effects, hormones can alter the functional activity, and sometimes the structure, of just one organ or tissue or various numbers of them.

[G. hormōn, pres. part. of hormaō, to rouse or set in motion]

hormone(s) (hôr´mōn[z]),

n.pl the biochemical secretions of the endocrine glands that, in relatively small quantities, partially regulate the physiologic activity of the tissues, organs, organ systems, and other endocrine glands, and of the nervous system itself. Its secretions are conducted and distributed throughout the body by the circulation of the bloodstream and tissue fluids.

n.pl the hormones secreted by adrenal medulla, including two catecholamines: epinephrine and norepinephrine.

hormones, adrenocortical,

n the steroid hormones secreted by the adrenal cortex that are biologically active in one or more of the following states: stress, inflammation, metabolism of carbohydrates, proteins, electrolytes, and water.

n a hormone of the posterior pituitary gland that encourages resorption of water by acting on the epithelial cells of the distal portion of the renal tubule. It raises blood pressure by its effect on the peripheral blood vessels and exerts an antidiuretic effect (antifacultative resorption of water in the renal tubules). An absence of antidiuretic hormone causes diabetes insipidus.

n a glycoprotein secreted by placental tissue early in normal pregnancy. This protein is also found in the urine or blood in association with chorioepitheliomas and some neoplastic diseases of the testes.

n the ovarian or adrenal hormones (e.g., estradiol, estrone, estriol) that are capable of stimulating changes of a cyclic nature in the genital system. One of the ovarian or adrenal hormones capable of affecting the cyclic changes of the female genital system. See also ACTH.

hormones, female sex,

n.pl the hormones secreted by the ovary. They include two main types: the follicular, or estrogenic, hormones produced by the graafian follicle, and the progestational hormones from the corpus luteum.

hormones, follicle-stimulating,

a pituitary tropic hormone that promotes the growth and maturation of the ovarian follicle and, with other gonadotropins, induces secretion of estrogens and possibly spermatogenesis.

hormones, gastrointestinal,

n the hormones that regulate motor and secretory activity of the digestive organs; that is, gastrin, secretin, and cholecystokinin.

n a hormone that is secreted by the anterior lobe of the pituitary gland and that exerts an influence on skeletal growth. As long as the growth apparatus is functional, it is responsive to the effects of the hormone.

hormones, ketogenic,

n the term used to describe a factor of the anterior pituitary hormone responsible for ketogenic effect. It is probably not an entity differing from known pituitary hormones.

hormones, lactogenic (galactin, mammotropin, prolactin),

n a pituitary hormone that stimulates lactation.

hormones, luteal,

n See hormones, progestational.

hormones, luteinizing,

n a pituitary hormone that causes ovulation and development of the corpus luteum from the mature graafian follicle. It is called an interstitial cell and stimulating hormone because of its action on the testis in maintaining spermatogenesis and because of its role in the development of accessory sex organs.

hormones, male sex (androgenic hormone, C-19 steroids),

n.pl the hormones found in the testes, urine, and blood. Included are testosterone found in the testes, andosterone excreted into the urine, and dehydro-3-epiandrosterone found in the blood.

hormones, melanocyte-stimulating (MSH, intermedin),

n a hormone of the middle lobe of the pituitary gland that increases melanin deposition by the melanocytes of the skin.

n.pl the C-19 corticosteroids that have androgenic and protein anabolic effects.

hormones, parathyroid,

n the secretory product of the parathyroid glands that promotes bone resorption and increases renal resorption of calcium and magnesium and diminishes that of phosphate. Excessive secretion produces generalized bone resorption, formation of fibrous marrow in the spongiosa, and, in young individuals, hypocalcification of the teeth.

hormones, pituitary,

n.pl the hormones of the anterior lobe of the pituitary gland, including the growth hormones (somatotropin 1, lactogenic hormone, prolactin, galactin, mammotropin) and pituitary tropins (gonadotropins, thyrotropic hormone, and ACTH). Whether or not a true diabetogenic pituitary hormone exists is a question. The melanocyte-stimulating hormone is secreted by the middle lobe of the pituitary gland, and vasopressin and oxytocin are secreted by the posterior lobe of the pituitary gland.

n a factor in the secretions of the adrenal cortex related to the regulation of carbohydrate metabolism.

hormones, sex,

n.pl the steroid hormones that are produced by the testes and ovaries and that control secondary sex characteristics, the reproductive cycle, development of the accessory reproductive cycle, and development of the accessory reproductive organs. Also included are the gonadotropins produced by the pituitary gland.

hormones, somatotropic,

n See hormone, growth.

hormones, steroid,

n.pl a group of biologically active organic compounds that are secreted by the adrenal cortex, testes, ovary, and placenta, and that have in common a cyclopentanoperhydrophenanthrene nucleus.

n.pl the hormones elaborated by the testes (mainly testosterone) that promote the growth and function of the male genitalia and secondary sex characteristics and that have potent protein anabolic effects.

hormones, thyroid,

n.pl the hormonal variants, including thyroxin and triiodothyronine, derived from the thyroid gland. They act as a catalyst for oxidative processes of the body cell and thus regulate the rates of body metabolism and stimulate body growth and maturation.

hormone

a chemical transmitter substance produced by cells of the body and transported by the bloodstream and other means to the cells and organs which carry specific receptors for the hormone and on which it has a specific regulatory effect.

Hormones act as chemical messengers to body organs, stimulating certain life processes and retarding others. Growth, reproduction, control of metabolic processes, sexual attributes and behavior are dependent on hormones.

Hormones are produced by various organs and body tissues, but mainly by the endocrine glands, such as the pituitary, thyroid and gonads (testes and ovaries). Each gland apparently manufactures several kinds of hormones; the adrenal glands alone produce more than 25 varieties. The total number of hormones is still unknown, but each has its unique function and structure. After a hormone is discharged by its parent gland into the capillaries or the lymph, it may travel a circuitous path through the bloodstream to exert influence on cells, tissues and organs (target organs) far removed from its site of origin.

adrenomedullary h's

substances secreted by the adrenal medulla, including epinephrine and norepinephrine.

androgenic h's

the masculinizing hormones, androstenedione and testosterone.

hormone assay

modern techniques include the use of competitive protein binding assay and radioimmunoassay.

calciotropic hormone

any hormone which is specifically involved in the homeostatic regulation of serum calcium levels through their effects on bone and other organs, e.g. parathyroid hormone, calcitonin.

corpus luteum hormone

progesterone.

cortical hormone

corticosteroid.

ectopic h's

those secreted by tumors of nonendocrine tissues but having the same physiological effects as their normally produced counterparts. It is not known exactly how the synthesis and secretion of endocrine hormones from nonendocrine tissues occurs. Most of these tumors are derived from tissues that have a common embryonic origin with endocrine tissues. When the cells undergo neoplastic transformation, they can revert to a more primitive stage of development and begin to synthesize hormones.

enteric hormone

hormone secreted by endocrine cells in the wall of the intestine or stomach or in the pancreas. Includes gastrin, cholecystokinin, secretin, gastric inhibitory polypeptide, enteroglucagon, motilin, neurotensin, 5-HT, substance P, pancreatic polypeptide, somatostatin.

estrogenic h's

substances capable of producing certain biological effects, the most characteristic of which are the changes which occur in mammals at estrus; the naturally occurring estrogenic hormones are β-estradiol, estrone and estriol.

gonadal h's

steroids in birds which affect development of the reproductive tubular system, head decorations, feathers, squawk, behavior.

hormone herbicide

substances sprayed on plants which exert a lethal hormonal effect on the entire plant. See also hormone weedkiller (below).

those stored and released by the neurohypophysis, i.e. oxytocin and vasopressin.

peptide h's

peptide molecules which exert their effects only on target cells that carry the hormone-specific receptors.

placental hormone

one secreted by the placenta, including chorionic gonadotropin, relaxin, and other substances having estrogenic, progestational or adrenocorticoid activity. See also placental hormones.

progestational h's

substances, including progesterone, that are concerned mainly with preparing the endometrium for nidation of the fertilized ovum if conception has occurred. See also progestational agent.

hormone receptors

the presence of hormone-specific receptors on cells is the means of determining which cells respond to the circulating hormones. The number of receptors on each cell is one of the ways of regulating the degree of response.

includes 2,4-D, 2,4,5-T, MCP, silvex, dalapon. See also tcdd, hcdd and dioxin.

Patient discussion about Hormone

Q. does the growth hormone have side effects and what are they?

A. Yes, it does, and not a few. They include, among others, pain in the joints, carpal tunnel syndrome, diabetes, pain at the injection site, problems with the thyroid gland, ear problems and many others. You may read more about side effects of growth hormone treatment (called Mecasermin or Somatropin) here: http://www.drugs.com/ppa/mecasermin.html

Q. what is the effect of hormones during pregnancy on a woman's temper?

Q. What types of hormonal changes caused by fibromyalgia? Fibromyalgia affects hormones because I feel pain in my back bone. What types of hormonal changes caused by fibromyalgia?

A. Have you ever checked your back pain with a doctor? It may or may not be due to fibromyalgia. Low serotonin levels, low growth hormone levels, and low levels of neuropeptide Y, a component of the feel-good hormone neurotransmitter norepinephrine have been associated with fibromyalgia. Elevated levels of substance P acts as a neurotransmitter and signals the body to experience pain. These pains have also been observed in the spinal cord of fibromyalgia patients.

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